Related subject matter is disclosed in a U.S. patent application entitledxe2x80x9cMethod for Enhancing Electron Emission in a Field Emission Device, xe2x80x9d filed on even date herewith, and assigned to the same assignee.
1. Field of the Invention
The present invention relates, in general, to field emission devices and, more particularly, to the structure of electrodes of the cathode plate of a field emission device.
2. Background of the Invention
It is known in the art that the electron emitters of a field emission device can become contaminated during the operation of the field emission device. The contaminated emissive surfaces typically have electron emission properties that are inferior to those of the initial, uncontaminated emissive surfaces. Several schemes have been proposed for conditioning the electron emitters and removing contaminants from the emissive surfaces thereof.
For example, it is known in the art to decontaminate or condition the emissive surfaces by scrubbing them with an electron beam provided by the electron emitter structures. An example of this scheme is described in U.S. Pat. No. 5,587,720, entitled xe2x80x9cField Emitter Array and Cleaning Method of the Samexe2x80x9d by Fukuta et al. However, this type of scheme can result in inefficient cleaning due to the electronic bombardment of surfaces other than the electron emissive surfaces, which can result in undesirable desorption of contaminants.
It is also known in the art to decontaminate or condition the emissive surfaces by applying a high, positive voltage pulse to the gate extraction electrode. This scheme is described in U.S. Pat. No. 5,639,356, entitled xe2x80x9cField Emission Device High Voltage Pulse System and Methodxe2x80x9d by Levine. Levine teaches that the high, positive voltage pulse increases the electric field at the emissive surfaces, thereby decreasing the adhesion energy of absorbates and facilitating the desorption of contaminants. However, this method does not provide the conditioning benefits realized from an electron scrubbing technique, wherein the emissive surfaces are bombarded with electrons.
Accordingly, there exists a need for an improved field emission device, which overcomes at least these shortcomings of the prior art.